Looks like it might be a spring type retainer clip. Maybe spread it at the top where the gap is and slide it off the latch? Here's a shot of the FAM page.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
